Modeling time-varying growth using a generalized von Bertalanffy model with application to bloater (Coregonus hoyi) growth dynamics in Lake Michigan
Canadian Journal of Fisheries and Aquatic Sciences
Abstract has subscript/superscript to be fixed
By: Emily B. Szalai, Guy W. Fleischer, and James R. Bence
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Abstract
A concurrent increase in lakewide abundance and decrease in size-at-age of bloater (Coregonus hoyi) in Lake Michigan have suggested density-dependent growth regulation. We investigated these temporal patterns by fitting a dynamic von Bertalanffy model and lengthweight relationship with time-varying parameters to mean length- and weight-at-ages (ages 17) from annual surveys (1965-1999). We modeled yearling length, asymptotic size (L‰), and the parameters of a power relationship between mean weight and mean length (α and β) as changing slowly over time using a random walk model. The Brody growth coefficient (k) was modeled as a linear function of L‰ with year-specific random deviations. Our results support a positive relationship between L‰ and k, indicating that under conditions supporting larger asymptotic lengths, individuals approach the asymptote more rapidly. We explored the relationship between year-specific growth parameters and indices of lakewide bloater abundance and found evidence of density-dependent growth. However, in the most recent years, L‰ and yearling length have remained low in Lake Michigan despite low bloater abundances, suggesting the occurrence of a fundamental shift in the food web.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Modeling time-varying growth using a generalized von Bertalanffy model with application to bloater (Coregonus hoyi) growth dynamics in Lake Michigan |
| Series title | Canadian Journal of Fisheries and Aquatic Sciences |
| DOI | 10.1139/f03-003 |
| Volume | 60 |
| Issue | 1 |
| Year Published | 2003 |
| Language | English |
| Publisher | NRC Research Press |
| Publisher location | Ottawa, ON |
| Contributing office(s) | Great Lakes Science Center |
| Description | 12 p. |
| Larger Work Type | Article |
| Larger Work Subtype | Journal Article |
| Larger Work Title | Canadian Journal of Fisheries and Aquatic Sciences |
| First page | 55 |
| Last page | 66 |
| Country | United States;Canada |
| Google Analytic Metrics | Metrics page |